修剪/剥离numpy数组的零

如何删除numpy数组的前导/尾随零？

import numpy as np
a = np.array([0,0,0,3,2,-1,0,0,7,9,13,0,0,0,0,0,0,0])

#Desired output
[3,2,-1,0,0,7,9,13]

这不起作用:

a[a != 0]    

因为它会删除所有零,包括里面的零.

用途numpy.trim_zeros:

>>> import numpy as np
>>> a = np.array([0,0,0,3,2,-1,0,0,7,9,13,0,0,0,0,0,0,0])
>>> np.trim_zeros(a)
array([ 3,  2, -1,  0,  0,  7,  9, 13])